Right-click the installer and select Run as Administrator .
This driver is for the AC'97 codec only. It will not work for modern "Realtek High Definition Audio" (ALC series) hardware. Installation Instructions draiver realtek ac97 4 06 skachat
Check the BIOS/UEFI settings to ensure the "Onboard Audio" is enabled and set to "AC97" mode rather than "Auto" or "HD Audio." Right-click the installer and select Run as Administrator